Heat dissipator for otptical writing and/or reproducing apparatus

ABSTRACT

Disclosed is a heat dissipator for an optical writing and/or reproducing apparatus. The heat dissipator comprises a main base having mounted thereto a plurality of parts including at least one motor for optical writing and/or reproduction; a circuit board positioned below the main base and having installed thereon elements for controlling the parts; a heat generating element formed with a plurality of leads which are connected to a circuit pattern of the circuit board; a heat conduction member brought into contact with at least the leads, for receiving heat generated in the heat generating element; and a cabinet brought into contact with the heat conduction member and formed with an element accommodating section and/or a pair of protrusions which are shaped to be functionally associated with an outer surface of the heat generating element to ensure that the heat dissipating member is brought into close contact with the leads of the heat generating element.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a heat dissipator for an opticalwriting and/or reproducing apparatus, and more particularly, the presentinvention relates to a heat dissipator for an optical writing and/orreproducing apparatus, which is constructed to properly dissipate heatgenerated in a heat generating element, especially, a drive IC(integrated circuit) while the optical writing and/or reproducingapparatus is driven.

[0003] 2. Description of the Related Art

[0004] Generally, in an optical writing and/or reproducing apparatussuch as a disk drive, a great amount of heat is generated duringoperation. In an optical writing and/or reproducing apparatus, heatgenerating parts include a loading motor for producing power needed toload and eject an optical disk, a spindle motor for rotating the opticaldisk, an optical pick-up for writing and/or reproducing data on and/orfrom the optical disk, a step motor for driving the optical pick-up, andelements installed on a circuit board for controlling operation of theoptical writing and/or reproducing apparatus.

[0005] If generated heat is not properly dissipated out of the opticalwriting and/or reproducing apparatus, not only the corresponding heatgenerating source but also surrounding parts can be adversely affectedby the heat, and thereby, an operational error can be caused in theoptical writing and/or reproducing apparatus.

[0006] Specifically, among the elements installed on the circuit boardfor controlling operation of the optical writing and/or reproducingapparatus, a drive IC for controlling driving of the motors generates asubstantial amount of heat when compared to the other elements.

[0007]FIG. 1 is a cross-sectional view illustrating a conventional heatdissipator for an optical writing and/or reproducing apparatus.

[0008] Referring to FIG. 1, an optical writing and/or reproducingapparatus includes a main base 30, and a circuit board 40 positionedbelow the main base 30. Elements for controlling operation of theoptical writing and/or reproducing apparatus are installed on thecircuit board 40. A spindle motor, a loading motor and a step motor (notshown) are installed on the main base 30.

[0009] Among the elements installed on the circuit board 40, since adrive IC 42 continuously controls driving of the motors, it consumes alarge amount of power and thereby generates a substantial amount of heatwhen compared to the other elements. For this reason, the drive IC 42 isinstalled on a lower surface 40 b of the circuit board 40 so as not toadversely influence, by heat, surrounding elements including an RF(radio frequency) IC and a DSP (digital signal processor) IC which areinstalled on an upper surface 40 a of the circuit board 40. At thistime, the drive IC 40 is installed in a manner such that outer leads 43externally formed thereon are bonded to the lower surface 40 b of thecircuit board 40.

[0010] Hereafter, the conventional heat dissipator for dissipating heatgenerated in the drive IC 42 will be described in detail.

[0011] The heat dissipator includes a lower cabinet 51 b which ispositioned to face the lower surface 40 b of the circuit board 40 and aheat dissipating conduction member 54 which is interposed between thelower cabinet 51 b and a molding section 42 a of the drive IC 42. Thelower cabinet 51 b delimits an outer contour of the optical writingand/or reproducing apparatus and is made of a metallic material. Theheat conduction member 54 functions to dissipate or conduct the heatgenerated in the drive IC 42. Over a region where the lower cabinet 51 bfaces the molding section 42 a of the drive IC 42, the lower cabinet 51b is formed with an upward protrusion 51 c which projects toward thedrive IC 42 to allow the heat dissipating conduction member 54 to bebrought into close contact with the molding section 42 a of the drive IC42.

[0012] At this time, the heat conduction member 54 is not brought intocontact with the outer leads 43 which serve to connect the drive IC 42to the circuit board 40.

[0013] Concretely speaking, between the drive IC 42 installed on thelower surface 40 b of the circuit board 40 and the lower cabinet 51 bfacing the drive IC 42, there is interposed the heat conduction member54 in a manner such that it is brought into close contact with themolding section 42a of the drive IC 42. As a consequence, heat generatedin the molding section 42 a of the drive IC 42 is transmitted throughthe heat conduction member 54 to the lower cabinet 51 b to be dissipatedto the outside.

[0014] However, the conventional heat dissipator constructed asmentioned above suffers from defects as described below.

[0015] While heat generated inside the drive IC 42 is first conducted toa molding material, that is, the molding section 42 a serving as anencapsulant, and then transmitted to the lower cabinet 51 b, in actualfact, since a considerable portion of the heat generated inside thedrive IC 42 is conducted to the outer leads 43 made of a metallicmaterial, the outer leads 43 have a higher temperature than the moldingmaterial. Resultingly, as heat of the outer leads 43 is transmitted to acircuit pattern formed on the circuit board 40, the circuit pattern islikely to be thermally damaged.

[0016] Also, because the heat conduction member 54 is installed over theregion which faces only a lower surface of the molding section 42 a ofthe drive IC 42, heat of side surfaces of the drive IC 42 and heat ofthe outer leads 43 cannot be properly conducted to the heat dissipatingconduction member 54. Therefore, heat as a whole, generated in theentire drive IC 42, cannot be properly transmitted to the lower cabinet51 b.

[0017] The reason for this is that only heat of the lower surface of themolding section 42 a of the drive IC 42 is conducted to the heatconduction member 54 to be dissipated to the outside, and heat of theside surfaces of the drive IC 42 and heat of the outer leads 43 aredissipated to the outside only by convection through air.

SUMMARY OF THE INVENTION

[0018] Accordingly, the present invention has been made in an effort tosolve the problems occurring in the related art, and an object of thepresent invention is to provide a heat dissipator for an optical writingand/or reproducing apparatus, which is constructed to properly dissipateheat generated in the optical writing and/or reproducing apparatus,thereby improving operational reliability of the optical writing and/orreproducing apparatus.

[0019] According to one aspect of the present invention, there isprovided a heat dissipator for an optical writing and/or reproducingapparatus, comprising: a main base having mounted thereto a plurality ofparts including at least one motor for optical writing and/orreproduction; a circuit board positioned below the main base and havinginstalled thereon elements for controlling the parts; a heat generatingelement formed with a plurality of leads which are connected to acircuit pattern of the circuit board; a heat conduction member broughtinto contact with at least the leads, for receiving heat generated inthe heat generating element; and a cabinet brought into contact with theheat conduction member and formed with an element accommodating sectionand/or a pair of protrusions which are shaped to be functionallyassociated with an outer surface of the heat generating element toensure that the heat conduction member is brought into close contactwith the leads of the heat generating element.

[0020] According to another aspect of the present invention, there isprovided a heat dissipator for an optical writing and/or reproducingapparatus, comprising: a heat generating element installed on a circuitboard and having a molding section which is formed with a plurality ofleads connected to a circuit pattern of the circuit board; a cabinetformed with a pair of protrusions which project toward the heatgenerating element to allow a portion of heat generated in the heatgenerating element, which portion is conducted to the leads, to bedissipated to the outside; and a heat conduction member interposedbetween the cabinet and the heat generating element and brought intocontact with at least the leads and/or the pair of projections.

[0021] According to still another aspect of the present invention, thereis provided a heat dissipating structure adapted for dissipating heatgenerated in an optical writing and/or reproducing apparatus,comprising: a heat generating element having a molding section which isformed with a plurality of leads; a cabinet formed with an elementaccommodating section for accommodating the heat generating element anda pair of protrusions which delimit the element accommodating section;and a heat conduction member interposed between the heat generatingelement and the cabinet, for being brought into contact with the leadsand the molding section and at the same time the element accommodatingsection and the pair of protrusions, whereby heat of the leads istransmitted to the protrusions to enhance a heat dissipation efficiency.

[0022] As described above, in the heat dissipator for an optical writingand/or reproducing apparatus according to the present invention, anelement accommodating section is formed on a lower cabinet in a mannersuch that it is functionally associated with outer surfaces and outerleads of a heat generating element, and a heat conduction member isinterposed between the element accommodating section and the heatgenerating element.

[0023] Hence, according to the present invention, advantages areprovided in that, since heat is transmitted from the outer surfaces,that is, a lower surface and both side surfaces and the outer leads ofthe heat generating element to the heat conduction member, anddissipated through the lower cabinet to the outside, heat as a whole,generated in the heat generating element, can be properly dissipated tothe outside. Also, because performance degradation of the heatgenerating element and surrounding parts due to overheating isprevented, operational reliability of the optical writing and/orreproducing apparatus can be improved.

[0024] Further, in the present invention, due to the fact that a size ofthe heat dissipating member is increased to be able to cover the entiredrive IC including the outer leads, a heat dissipation efficiency isenhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above objects, and other features and advantages of thepresent invention will become more apparent after a reading of thefollowing detailed description when taken in conjunction with thedrawings, in which:

[0026]FIG. 1 is a cross-sectional view illustrating a conventional heatdissipator for an optical writing and/or reproducing apparatus;

[0027]FIG. 2 is an exploded perspective view illustrating an opticalwriting and/or reproducing apparatus in which a heat dissipator inaccordance with an embodiment of the present invention is used; and FIG.3 is a cross-sectional view illustrating the heat dissipator accordingto the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] Reference will now be made in greater detail to a preferredembodiment of the invention, an example of which is illustrated in theaccompanying drawings. Wherever possible, the same reference numeralswill be used throughout the drawings and the description to refer to thesame or like parts.

[0029]FIG. 2 is an exploded perspective view illustrating an opticalwriting and/or reproducing apparatus in which a heat dissipator inaccordance with an embodiment of the present invention is used. In thepresent invention, the parts that correspond to those of FIG. 1 will bedesignated by the same reference numerals.

[0030] Describing in detail, with reference to FIG. 2, a construction ofan optical writing and/or reproducing apparatus which adopts a heatdissipator in accordance with an embodiment of the present invention,the optical writing and/or reproducing apparatus includes a pick-up base(not shown) serving as a frame. A spindle motor for rotating an opticaldisk and an optical pick-up for radiating light to write and/orreproduce data on and/or from the optical disk are installed on thepick-up base. The optical writing and/or reproducing apparatus furtherincludes a main base 30, a circuit board 40, a drive IC 42, a pluralityof outer leads 43, upper and lower cabinets 51 a and 51 b, and a heatconduction member 54 55. A tray 34 for loading and ejecting the opticaldisk into and from the optical writing and/or reproducing apparatus isarranged on the main base 30. The circuit board 40 is positioned belowthe main base 30, and a variety of elements for driving the spindlemotor, the optical pick-up, etc. are installed on the circuit board 40.The drive IC 42 is installed on a lower surface of the circuit board 40to face an upper surface of the lower cabinet 51 b. The plurality ofouter leads 43 project out of both side surfaces of the drive IC 42 andare bonded to the circuit board 40 by soldering. The upper and lowercabinets 51 a and 51 b which constitute a cover 50 delimit an outercontour of the optical writing and/or reproducing apparatus and are madeof a metallic material. The heat conduction member 54 55 functions totransmit heat generated in the drive IC 42 to the lower cabinet 51 bthereby to dissipate the heat to the outside.

[0031] Describing in further detail the construction of the opticalwriting and/or reproducing apparatus which adopts the heat dissipator inaccordance with the embodiment of the present invention, an uppersurface 35 of the tray 34 serves as a disk seating surface on which theoptical disk is seated upon being loaded and ejected. A clamp 36 isdisposed above the tray 34 to clamp the optical disk to a turntable (notshown) provided to the spindle motor.

[0032] A connection socket 45 for permitting connection of the opticalwriting and/or reproducing element to another unit is installed at oneend of the circuit board 40. The upper cabinet 51 a defines an uppersurface and both side surfaces of the optical writing and/or reproducingapparatus, and the lower cabinet 51 b defines a lower surface of theoptical writing and/or reproducing apparatus. However, it is to bereadily understood that the present invention is not limited to such astructure, and the lower cabinet 51 b can define a lower surface andboth side surfaces of the optical writing and/or reproducing apparatus.

[0033] Generally, a rear surface of the optical writing and/orreproducing apparatus is defined by the main base 30, and a frontsurface is defined by a separate front plate (not shown).

[0034] According to the present invention, over a region where the lowercabinet 51 b faces the drive IC 42, the lower cabinet 51 b is formedwith an element accommodating section 52. The element accommodatingsection 52 defines a space which can accommodate therein the entiredrive IC 42. The element accommodating section 52 has a size which islarger than a width of the drive IC 42. The element accommodatingsection 52 is delimited by a pair of protrusions 53 which project towardthe circuit board 40 at left and right sides of the elementaccommodating section 52. The pair of protrusions 53 are formed in amanner such that they face the outer leads 43 of the drive IC 42. In theillustrated embodiment, the drive IC 42 has a body which possesses aparallelepiped-shaped configuration, and the plurality of outer leads 43which project outward from both side surfaces of the body. At this time,a lower surface and both side surfaces of the body of the drive IC 42and the outer leads 43 projecting out of both side surfaces of the driveIC 42 are functionally associated with the upper surface of the lowercabinet 51 b.

[0035] The element accommodating section 52, which is associated withthe lower surface of the body of the drive IC 42, is formed to have thesame height as a remaining portion of the lower cabinet 51 b. And, thepair of protrusions 53, which are associated with the outer leads 43,project toward the circuit board 40 to extend upward beyond the lowersurface of the body of the drive IC 42.

[0036] The heat conduction member 55 is made of soft silicon such as GAPPAD™ manufactured by BERGQUIST or Raychem™ manufactured by Tyco.

[0037]FIG. 3 is a cross-sectional view illustrating the heat dissipatoraccording to the present invention.

[0038] The construction of the heat dissipator according to the presentinvention will be described below in further detail with reference toFIG. 3.

[0039] The heat conduction member 54 55 is attached to the drive IC 42which is installed on the lower surface of the circuit board 40. Theheat conduction member 54 55 is made of a soft material and thereforecan be freely deformed. A size of the heat conduction member 54 55 isdetermined in a manner such that it can be brought into sufficientcontact with the lower surface and the outer leads 43 of the drive IC42. Then, by assembling the lower cabinet 51 b with respect to the heatconduction member 54 55, the body of the drive IC 42 is accommodated inthe element accommodating section 52, and the pair of protrusions 53bias the heat conduction member 54 55 to be brought into close contactwith the outer leads 43.

[0040] Hereafter, working effects of the heat dissipator for an opticalwriting and/or reproducing apparatus according to the present invention,constructed as mentioned above, will be described in detail.

[0041] While the optical writing and/or reproducing apparatus isoperated, heat is generated in a number of parts. The generated heatshould be properly dissipated to the outside to prevent thecorresponding heat generating source and surrounding parts to beadversely affected by the heat. In the optical writing and/orreproducing apparatus, heat generating parts include the opticalpick-up, the spindle motor, a step motor, and the variety of elementsincluding the drive IC 42.

[0042] The present invention is focused on dissipation of heat generatedin the variety of elements including the drive IC 42. Description of thepresent embodiment will be given mainly in relation with the drive IC42. While the optical disk is driven, a considerable amount of heat isgenerated in the drive IC 42 installed on the circuit board 40. Thegenerated heat is partially dissipated to the outside through the lowersurface and both side surfaces of the drive IC 42 and is partiallyconducted to the outer leads 43 made of a metallic material.

[0043] The heat conduction member 55, which is located in the elementaccommodating section 52 to be functionally associated with the lowersurface and the outer leads 43 of the drive IC 42, is brought intocontact with the lower surface and the outer leads 43 of the drive IC42. Therefore, as the heat conduction member 55 receives heat from thelower surface and the outer leads 43 of the drive IC 42 and transmitsthe heat to the lower cabinet 51 b, the heat is dissipated to theoutside through the lower cabinet 51 b.

[0044] That is to say, heat generated in the drive IC 42 is transmittedthrough its entire outer surface and the outer leads 43 to the heatconduction member 55. Accordingly, almost all of the heat generated inthe drive IC 42 can be transmitted to the heat conduction member 55.

[0045] Experimental temperature data obtained by the heat dissipatorsaccording to the present invention and the conventional art,respectively, are presented below in TABLE 1. TABLE 1 ConventionalPresent lower cabinet lower cabinet Optical pick-up 63° C. 62° C.Spindle motor 69° C. 72° C. Step motor 71° C. 74° C. DSP IC 75° C. 76°C. RF IC 83° C. 84° C. Drive IC 102° C.  86° C. Lower cabinet 60° C. 63°C. Internal Space 47° C. 46° C.

[0046] As can be readily seen from TABLE 1, in the case that the lowercabinet structure according to the present invention is applied to theheat dissipator, the drive IC 42 which usually has a highest temperaturein an optical writing and/or reproducing apparatus is significantlyreduced in its temperature to 86° C. when compared to its temperature of102° C. under the conventional art. Further, a temperature of the lowercabinet 51 b is slightly increased from 60° C. to 63° C. As a result, aperson skilled in the art will readily recognize that, in the presentinvention, heat generated in the drive IC 42 is properly transmitted tothe lower cabinet 51 b through the heat conduction member 55 anddissipated to the outside.

[0047] Of course, it is to be noted that the heat dissipator accordingto the present invention can be employed not only in the drive IC butalso other heat generating elements which are installed on the circuitboard.

[0048] Preferably, the heat dissipating member comprises a heatdissipating pad.

[0049] More preferably, the heat dissipating pad is made of a suitablematerial such as silicon.

[0050] In the preferred embodiment of the present invention, as a heatgenerating element, the drive IC which is formed at both side surfacesthereof with the plurality of leads, was described. However, the presentinvention is not limited to this configuration of the drive IC, and itis possible to use a drive IC which is formed, at its four sidesurfaces, with leads. In this case, it is to be understood that fourprotrusions must be formed on the lower cabinet 51 b.

[0051] As described above, in the present invention, since heat of thelower and side surfaces and the outer leads 43 of the drive IC 42serving as a heat generating element in the optical writing and/orreproducing apparatus is transmitted to the heat conduction member 55and dissipated to the outside through the lower cabinet 51 b, properheat dissipation is ensured.

[0052] Thus, because performance degradation of the heat generatingelement and surrounding parts due to overheating is prevented,operational reliability of the optical writing and/or reproducingapparatus can be improved.

[0053] Moreover, due to the fact that the element accommodating section52 is formed to have the same height as the remaining portion of thelower cabinet 51 b, the entire height of the optical writing and/orreproducing apparatus can be decreased.

[0054] In the drawings and specification, there have been disclosedtypical preferred embodiments of the invention and, although specificterms are employed, they are used in a generic and descriptive senseonly and not for purposes of limitation, the scope of the inventionbeing set forth in the following claims.

What is claimed:
 1. A heat dissipator for an electrical apparatus, comprising: a circuit board having installed thereon elements for controlling parts; a heat generating element formed with a plurality of leads which are connected to a circuit pattern of the circuit board; a heat conduction member brought into contact with at least the leads, for receiving heat generated in the heat generating element; and a cabinet brought into contact with the heat conduction member and formed with an element accommodating section and/or a pair of protrusions which are shaped to be functionally associated with an outer surface of the heat generating element to ensure that the heat conduction member is brought into close contact with the leads of the heat generating element.
 2. The heat dissipator as set forth in claim 1, wherein the heat conduction member is made of soft silicon.
 3. The heat dissipator as set forth in claim 1, wherein the heat generating element comprises a drive IC.
 4. The heat dissipator as set forth in claim 1, wherein the heat conduction member is simultaneously brought into contact with a molding section and the leads of the heat generating element, and the element accommodating section and/or the pair of protrusions enable the heat conduction member to be brought into close contact with the molding section and the leads of the heat generating element.
 5. The heat dissipator as set forth in claim 1, wherein the leads are formed at side surfaces of the heat generating element.
 6. A heat dissipator for an electrical apparatus, comprising: a heat generating element installed on a circuit board and having a molding section which is formed with a plurality of leads connected to a circuit pattern of the circuit board; a cabinet formed with a pair of protrusions which project toward the heat generating element to allow a portion of heat generated in the heat generating element, which portion is conducted to the leads, to be dissipated to the outside; and a heat conduction member interposed between the cabinet and the heat generating element and brought into contact with at least the leads and/or the pair of projections.
 7. The heat dissipator as set forth in claim 6, wherein the heat conduction member is made of soft silicon.
 8. The heat dissipator as set forth in claim 6, wherein the heat generating element comprises a drive IC.
 9. The heat dissipator as set forth in claim 6, wherein the cabinet is formed with an element accommodating section which enables the heat conduction member to be brought into close contact with the molding section of the heat generating element.
 10. The heat dissipator as set forth in claim 6, wherein the leads are formed at side surfaces of the heat generating element.
 11. A heat dissipating structure adapted for dissipating heat generated in an electrical apparatus, comprising: a heat generating element having a molding section which is formed with a plurality of leads; a cabinet formed with an element accommodating section for accommodating the heat generating element and a pair of protrusions which delimit the element accommodating section; and a heat conduction member interposed between the heat generating element and the cabinet, for being brought into contact with the leads and the molding section and at the same time the element accommodating section and the pair of protrusions, whereby heat of the leads is transmitted to the protrusions to enhance a heat dissipation efficiency.
 12. The heat dissipating structure as set forth in claim 11, wherein the heat conduction member is made of soft silicon.
 13. The heat dissipating structure as set forth in claim 11, wherein the heat generating element comprises a drive IC.
 14. The heat dissipating structure as set forth in claim 11, wherein the heat conduction member comprises a heat dissipating pad.
 15. The heat dissipating structure as set forth in claim 11, wherein the leads are formed at side surfaces of the heat generating element.
 16. A heat dissipator for an electrical apparatus, comprising: a circuit board positioned having installed thereon elements for controlling parts; a heat generating element formed with a plurality of leads which are connected to a circuit pattern of the circuit board and producing heat during operation; a heat conduction member brought into contact with at least the leads, for receiving heat generated in the heat generating element; and a cabinet contact with the heat conduction member and having at least one protrusion to ensure that the heat conduction member being closely contacted with the leads of the heat generating element.
 17. The heat dissipator as set forth in claim 16, wherein the heat conduction member is made of soft silicon.
 18. The heat dissipator as set forth in claim 16, wherein the cabinet is formed with an element accommodating section which enables the heat conduction member to be contacted with a molding section of the heat generating element.
 19. The heat dissipator as set forth in claim 16, wherein the leads are formed at side surfaces of the heat generating element. 